Will subversion repository work over iSCSI

[Gal Aviel <ga...@chipx.co.il>]

Hi All,

I'm trying to push subversion in my company and I'd realy
appreciate any help ..

We're trying to evaluate subversion here but the IT manager is abit 
worried that subversion works only over local disks since these are 
usually not a part of the company backup scheme.

He wants the repos. to sit on our NAS, which supports 
iSCSI as well as NFS (I'm aware that the latter is not acceptable).

So will subversion work over iSCSI ? 

We will probably take a low-cost linux x86 machine for the server (I plan
to allow access to repos. only via subversion server, no local access).

Any help would be greatly appreciated !

Thanks - Gal.



  ================================
  Gal Aviel
  Chip Express (Israel) Ltd.
   
  Advanced Technology Center
  P.O.Box 2401, Haifa 31024 Israel
   
  Tel: +972-4-8550011 Ext. 272
  Fax: +972-4-8551122
  E-mail: mailto:gala@chipx.co.il
  WEB: http://www.chipexpress.com

  "The reasonable man adapts himself to the World.
  The unreasonable one persists in trying to adapt the 
  World to himself. Therefore, all progress depends upon
  the unreasonable man."

  G.B. Shaw
  Man & Superman : Maxims for Revolutionists. 
  ================================


---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@subversion.tigris.org
For additional commands, e-mail: users-help@subversion.tigris.org

Re: Will subversion repository work over iSCSI

[John Peacock <jp...@rowman.com>]

Ulrich Eckhardt wrote:
> As I understand it (and no, I didn't try) concurrent accesses to the DB are 
> only safe if it is on a local disk. However, if you run one single instance 
> of svnserve or apache serving a repository, it doesn't matter if that 
> repository is on a network share.

I'm not sure that even that last statement is completely accurate.  According to 
this:

	http://www.sleepycat.com/docs/ref/env/remote.html

only a single BDB instance can be allowed to interact with a database file that 
has been remotely mounted, and then _only_ if the filesystem supports full POSIX 
filesystem specs (there are caveats for both FreeBSD and some Linux filesystems 
on that page).  That second limitation is just as important as the first.

However, in the original poster's case, iSCSI is a transport layer which is much 
more like native SCSI or IDE, in that the local OS is reponsible for maintaining 
the filesystem (iSCSI connections are block-level devices IOW).  As such, there 
should be no problem (other than performance issues) with running BDB on those 
filesystems.  A month or so from now, I will be running a SAN box, so I'll be 
stress-testing Subversion on a SAN mount point...

John

-- 
John Peacock
Director of Information Research and Technology
Rowman & Littlefield Publishing Group
4501 Forbes Boulevard
Suite H
Lanham, MD  20706
301-459-3366 x.5010
fax 301-429-5748

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@subversion.tigris.org
For additional commands, e-mail: users-help@subversion.tigris.org

Re: Will subversion repository work over iSCSI

[Ulrich Eckhardt <ec...@satorlaser.com>]

Gal Aviel wrote:
> He wants the repos. to sit on our NAS, which supports
> iSCSI as well as NFS (I'm aware that the latter is not acceptable).
>
> So will subversion work over iSCSI ?
>
> We will probably take a low-cost linux x86 machine for the server (I plan
> to allow access to repos. only via subversion server, no local access).

As I understand it (and no, I didn't try) concurrent accesses to the DB are 
only safe if it is on a local disk. However, if you run one single instance 
of svnserve or apache serving a repository, it doesn't matter if that 
repository is on a network share. Using a local disk, you could access the 
repository via svnserve, apache and file at the same time.

One note on backup-strategies: it might be better to not backup the database 
itself but a dump (svnadmin dump) thereof, because that format is designed to 
remain constant regardless of the database layout, which used to change in 
the past. Using a cronjob to dump it on a iSCSI or NFS share might be a good 
option.

Uli


---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@subversion.tigris.org
For additional commands, e-mail: users-help@subversion.tigris.org